Productive areas are found where the stream's character changes. Confluences with smaller tributaries often create nutrient-rich seams and deeper holes that hold fish. Undercut banks along outside bends, especially those shaded by vegetation, provide cover for larger trout. Deep pools scoured out by current around large boulders or fallen timber are consistently reliable spots. Runs between riffles, where the water deepens and slows slightly, are perfect for nymphing.